Attaching Geotextile Lengths

[JimMorrissey]

What is the preferred method to attach one piece of fabric to another? Should I hand sew it, or spike it down with something. I've got a 12.5' wide roll and I need to attach another 4' for 16' total. Not sure what the technique is. I don't want to have to manually sew 1800' of fabric together. Maybe I don't need to do anything but overlap a bit.

 

[Farwell]

Jim,
If Geotextile is similar to landscaping barrier material, I have used hundreds of feet of the heavy material and have never had a problem, I overlap it about six inches. If I feel that the material may move I drive a landscaping or gutter nail through the material. If its on a hill and I think it may be a problem, prior to putting my rock or mulch on it I use a larger plastic stake designed for use with the material. I space them at about 36 inch intervals and overlap the lower sheet with the upper sheet and put a few of the nails in them where they overlap at 36 to 48 inch intervals.
Farwell

 

[Toiyabe]

Some geotextile materials can be welded, but normally they are just overlapped.

Some geotextiles are for strength, some are for filtering (i.e. to prevent materials from mixing) and a few do both. For a strength fabric you may want to use a larger overlap, for a filter fabric just enough to ensure complete coverage.

There's also erosion control fabrics, but that doesn't sound like what you're asking about.

 

[LarryD]

I think Farwell's overlap will work fine if your're careful not to tug the material while covering it. From the 02 WA state highway book...

2-12.3(1) Underground Drainage
Trench walls shall be smooth and stable. The geotextile shall be placed in a manner which will ensure intimate contact between the soil and the geotextile (i.e., no voids, folds,
or wrinkles).
The geotextile shall either be overlapped a minimum of 12 inches at all longitudinal and transverse joints, or the geotextile joints shall be sewn for medium survivability
drainage applications. In those cases where the trench width is less than 12 inches, the minimum overlap shall be the trench width.
In moderate survivability geotextile underdrain applications, the minimum overlapshall be 12 inches, or the geotextile joints shall be sewn, except where the geotextile is used in area drains. An area drain is defined as a geotextile layer placed over or under a horizontal to moderately sloping layer of drainage aggregate. For area drains, the geotextile shall be
overlapped a minimum of 2 feet at all longitudinal and transverse joints, or the geotextile joints shall be sewn together. The minimum initial lift thickness over the geotextile in the area drain shall be 12 inches.
In all cases, the upstream geotextile sheet shall overlap the next downstream sheet.
2-12.3(2) Separation
The geotextile shall either be overlapped a minimum of 2 feet at all longitudinal and transverse joints, or the geotextile joints shall be sewn together. The initial lift thickness
shall be 6 inches or more.
2-12.3(3) Soil Stabilization
The geotextile shall either be overlapped a minimum, of 2 feet at all longitudinal and transverse joints, or the geotextile shall be sewn together. The initial lift thickness shall be 12 inches or more. Compaction of the first lift above the geotextile shall be by Method A (Section 2-03.3(14)C). No vibratory compaction will be allowed on the first lift.
2-12.3(4) Permanent Erosion Control and Ditch Lining
Unless otherwise specified in the Plans, the geotextile shall either be overlapped a minimum of 2 feet at all longitudinal and transverse joints, or the geotextile joints shall be
sewn together. If overlapped, the geotextile shall be placed so that the upstream strip of geotextile will overlap the next downstream strip. When placed on slopes, each strip shall
overlap the next downhill strip.
Placement of aggregate and riprap or other cover material on the geotextile shall start at the toe of the slope and proceed upwards. The geotextile shall be keyed at the top and the
toe of the slope as shown in the Plans. The geotextile shall be secured to the slope, but shall be secured loosely enough so that the geotextile will not tear when the riprap or other cover
material is placed on the geotextile. The geotextile shall not be keyed at the top of the slope until the riprap or other cover material is in place to the top of the slope.

 

[JimMorrissey]

Good stuff. Didn't know the geotextile must be so "intimate" with the base.....makes sense. I'll be careful not to let it sag or wrinkle while the first lift is being placed.

The rolls are 12.5' wide, so I'll run a full length then run half of another roll, which will give me a 2' + overlap. Perfect. I'll probably spike the fabric too to keep it tight. Excellent information. Thanks agian.

 

[dmccarty]

Jim,

I overlapped when I built the driveway. If I could get a 12-24 inche overlap that was great. Sometimes only a couple of inches. Does not seem to have mattered one way or the other for my driveway.

I did used small rocks to hold the fabric in place. Better than that was to use the shovel full of the gravel you are putting down.

Later,
Dan